Crystal Defenders is a defensive strategy game, in which the player must guard a path using troops taken straight from the Final Fantasy job classes, such as Soldiers, Archers and Black Mages. Every enemy who traverses the entire path means another crystal lost to the party.

The game has three modes: W1 teaches the player the basics, W2 introduces Power Crystals which add a layer of strategy, and W3 is filled with more complex maps.